Bacteriophages have become a promising approach as biocontrol agents due to the continuous unraveling of new information about its biology, host specificity, impacts on normal microflora and mammalian cells as well as ease of propagation (Shahrbabak, et al. Isolation, characterization and complete genome sequence of Phaxl: a phage of Escherichia coli O157:H7, Micro. 159, 1629-1638, 2013). Advanced technologies can ensure absence of virulence or antibiotic resistance genes increasing its efficacy and level of safety in phage therapy. In addition, bacteriophages that are highly-infective over a range of target groups and possess lytic life cycle that prevents recombination of its DNA with bacterial chromosome are key characteristics of excellent agents for biocontrol use. Because bacteriophages are bacterial predators, they can provide natural and non-antibiotic options that can reduce the incidence of foodborne pathogen contamination from bacteria, such as, for example, Shiga-toxin producing Escherichia coli (STEC) serogroups.
Specific and rapid detection of foodborne pathogens in the food system is significant for containment and prevention of human, animal and plant diseases (Singh, et al. Bacteriophage based probes for pathogen detection, Analyst, 137, 3405 2012). Biosensors overcome the limitations of traditional foodborne pathogen detection such as tedious and time consuming by providing reliable, specific and highly sensitive platforms with shorter turnaround time. More importantly, bio sensors circumvent the limitations of the traditional laboratory microbial screening by its hand-held features and portability for on-site rapid analysis and detection of significant groups of foodborne pathogens and toxins. Bacteriophages possess excellent host selectivity attributes and have been used as biorecognition elements for pathogen detection (Singh, et al. Recent Advances in Bacteriophage Based Biosensors for Food-Borne Pathogen Detection, Sensors, 13, 1763-1786, 2013).
The use of antibodies as recognition elements is very common in diagnostics and foodborne pathogen biosensing applications due to their availability and high affinity. Monoclonal and polyclonal antibodies provide selectivity and specificity when incorporated as receptors. However, the major drawbacks of antibodies that are constantly met by end-users include high costs of production, instability and that they are highly prone to contamination and degradation rendering them very impractical and unreliable recognition elements. In addition, cross-reactivity towards other strains or species and interference are innate to polyclonal antibodies.
Bacteriophages that exist in nature and are inexpensive to propagate may be alternatives to antibodies as biological recognition receptors as they are highly-specific to their host bacteria and very stable, which allows easy handling and storage. However, once a bacteriophage binds to and/or infects a target bacterium, the bacterium is time-limited in that it will be killed by the phage, and thus is difficult to detect directly.
All of the references cited herein, including U.S. Patents and U.S. Patent Application Publications, are incorporated by reference in their entirety.
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